1. Field of the Invention
The present invention relates to an alternator and, more specifically, to an alternator coupled to a drive via an adjustable speed planetary gear assembly.
2. Background Information
As is well known in the art, an alternator is a device structured to convert energy from a rotational motion into an alternating current. Generally, an alternator spins a magnet, or rotor, within an alternator housing and this spinning magnet induces electric currents in a set of stationary wire coils, or the stator. Most engine powered road vehicles include an alternator and the following description shall use a heavy-duty truck as an example; however, it is understood that the claimed invention may be used with any type of alternator and is not limited to vehicular use. That is, the invention relates to an alternator wherein the rotor is likely to spin at various speeds. Thus, the invention may be used in conjunction with other devices such as, but not limited to, a windmill structured to produce electricity. In a vehicle, an engine provides a source of rotation, such as, but not limited to the drive shaft or crank shaft. The source of rotation is coupled, typically, via a belt and/or shaft to a shaft that is fixed to the rotor and has an end extending outside the alternator housing, hereinafter a “rotor shaft assembly”. Thus, when the engine is operating, the source of rotation causes the rotor to rotate and creates the alternating current.
While this configuration is satisfactory, it does have disadvantages. For example, because the speed of the rotor is linked to the speed of the source of rotation, the frequency of the alternating current is directly dependent upon the speed of the source of rotation. This can be a disadvantage as the engine speed, as used in this example, typically varies between 600 to 2400 rpm which results in the frequency of the current varying between about 150 and 600 Hz. It would be advantageous to maintain the frequency of the current within a selected range between about 50 and 70 Hz, and more preferably about 60 Hz.